Low speed wind tunnel design for agricultural spray particle analysis

ABSTRACT

A wind tunnel device defines a cyclical tunnel to receive continuous airflow. Airflow is delivered through the tunnel to a testing region that includes a first portion carrying an arm including a spray tip configured to spray particulates in the testing region at an angle, and a second portion including an enlarged cutout region configured to receive the angled sprayed particulates. As airflow carries the angled spray particulates into the second portion, the enlarged cutout region enables the spray particulates to pass through and exit the second portion of the testing region. Analysis in the second region may be conducted through transparent walls free of openings to minimize exposure of the spray particulates to the exterior of the device. A scrubber is adapted to extract spray mist from the airflow as the airflow exits the testing region and is re-circulated through the cyclical tunnel.

CROSS-REFERENCED RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/199,531 filed on Mar. 6, 2014, issued as U.S. Pat. No. 9,116,068 onAug. 25, 2015, which is a continuation of U.S. patent application Ser.No. 13/614,522 filed on Sep. 13, 2012, issued as U.S. Pat. No. 8,689,619on Apr. 4, 2014, which claims priority to U.S. Provisional ApplicationNo. 61/588,058 filed on Jan. 18, 2012, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

This application relates to wind tunnel devices for agricultural sprayanalysis, and more particularly to wind tunnel devices configured assubstantially closed systems that reduce exposure to agricultural spraysduring analysis while providing for the aerodynamic flow of air andspray particulates.

BACKGROUND

Due to increasing concern about pest control costs and environmentalpollution associated with agricultural sprays, application of suchsprays requires precision and care. Considerable research on spray drifthas been conducted, but it remains a major problem associated with manyagricultural spray applications.

Field tests provide some information on factors influencing spray drift.However, field tests are limited by weather conditions that cannot becontrolled and often vary during a test. Due to non-controlledenvironment, assessing the influence of some variables on spray drift isdifficult. Consequently, laboratory tests are used to evaluate driftassociated with spray deposits discharged from spray tips at variouswind velocities in wind tunnels. However, wind tunnels are generallycostly and may expose the tester to the agricultural spray, which canhave negative health effects on the tester.

The US EPA will soon implement a new Drift Reduction Technology (DRT)program which would allow farmers and applicators to reduce the size ofbuffer zones required on some herbicide labels. DRT will need to becertified through the use of spray particle analysis or field trialsproving a reduction in fine droplets subject to off-target drift. As aresult, more frequent use of wind tunnels may be required forcertification.

SUMMARY

In view of the foregoing, there is a need to provide wind tunnel devicesthat are configured cost-effectively and that shield operators of thewind tunnel devices from exposure to potentially harmful agriculturalsprays. Accordingly, wind tunnel devices provided herein are configuredas substantially enclosed systems for transporting airflow through thesystem to carry agricultural spray droplets past an analyzer, capturingsubstantially all of the spray droplets, and re-circulating the airflowthrough the system. The closed systems may have a rectangular shape andmay include devices for facilitating an aerodynamic flow of the airthrough the system as well as transparent sidewalls free of openingsadjacent to the analyzer.

According to one implementation, a wind tunnel device includes asegmented enclosure configured with an enclosed interior defining acyclical tunnel for receiving continuous airflow therein. An airflowsystem delivers airflow through the tunnel including a testing regiontherein. In the testing region, a first portion carries an arm includinga spray tip configured to spray particulates in the testing region at anangle and a second portion includes an enlarged cutout region configuredto receive the angled spray particulates. The second portion with theenlarged cutout region accommodates the area covered by the angled sprayparticulates. The airflow carries the angled spray particulates from thespray tip into the enlarged cutout region such that the angled sprayparticulates pass through and exit the second portion of the testingregion. As the airflow exits the testing region, it returns to theairflow system through the enclosed interior defining of the cyclicaltunnel thereby re-circulating the airflow.

According to another implementation, a method of analyzing sprayparticulates in a wind tunnel involves providing a segmented enclosureconfigured with an enclosed interior defining a cyclical tunnel forreceiving continuous airflow therein; providing an airflow system and atesting region within the segmented enclosure such that the airflowsystem delivers airflow through the cyclical tunnel including thetesting region; providing the testing region with a first portioncarrying an arm including a spray tip configured to spray particulatesin the testing region at an angle and providing the testing region witha second portion including an enlarged cutout region for accommodatingthe area covered by the angled spray particulates and a transparentsidewall free of openings. Angled spray particulates are sprayed fromthe spray tip and are analyzed through the transparent sidewall free ofopenings. The airflow carries the angled spray particulates from thespray tip into the enlarged cutout region such that the sprayparticulates pass through and exit the second portion of the testingregion. The airflow is re-circulated through the enclosed interiordefining the cyclical tunnel as the airflow exits the testing region.

In yet a further implementation, a wind tunnel includes a fan, a firstsection, and second section, and a third section connected to form agenerally rectangular shape, wherein the fan, the first section, thesecond section, and the third section form a tunnel that allows for thepassage of air. A traversing arm is attached to the second section andadapted to receive a spray tip and to telescope and extend the spray tipinto the volume defined by the second section. A first expansion cutoutis attached the second section and forming a portion of a ceiling of thesecond section. A second expansion cutout is attached to the secondportion and forming a portion of a floor of the second section. An angleof expansion of the first and second expansion cutouts enables sprayparticles from the spray tip to pass through and exit the secondsection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of one embodiment of a wind tunneldevice according to certain implementations.

FIG. 2 shows a left side view of the wind tunnel device of FIG. 1.

FIG. 3 is a front view of the wind tunnel device of FIG. 1.

FIG. 4 is a right side view of the wind tunnel device of FIG. 1.

FIG. 5 is a top plan view of the wind tunnel device of FIG. 1.

FIG. 6 is a front left side view of the wind tunnel device of FIG. 1.

FIG. 7 is a view of an operating console that may be provided inconnection with the wind tunnel device of FIG. 1.

DETAILED DESCRIPTION

Research has shown that the most reliable data for spray particleanalysis comes from using a wind tunnel to move fine spray particlesaway from an analysis device to prevent duplicate measurements. Thisdisclosure relates, in part, to low speed wind tunnels used for analysisof spray particle size.

Wind tunnel devices provided herein may provide for accurate laseranalysis of spray particles, which may be used for: product development(such as spray tip development); formulation development (such as activeingredients, e.g., herbicides, and adjuvants, e.g., drift reducercompositions); product label development; drift reduction technologydevelopment (e.g., spray tips, active ingredients and adjuvants); andgrower and applicator training and education. Wind tunnel devices mayaccordingly be configured to test a variety of herbicide activeingredients, adjuvants, spray tips, and combinations of these toevaluate potential off-target movement.

FIG. 1 shows a perspective view of one embodiment of a wind tunneldevice 10 according to certain implementations. The wind tunnel device10 may include a series of segments or sections. Each of the sectionsmay include a first end and a second end, such as a ceiling and a floor,respectively, as well as sidewalls therebetween. The sections may begenerally rectangularly shaped and open at two sides to enable thesections to be interconnected. Some of the sections may be configured ascorners and may include two open sides arranged at a right angle. Forexample, as shown in FIG. 1, the wind tunnel device 10 may include a fan12, a first section 14, a second section 16, and a third section 18. Thefan 12 and the three sections 14, 16, 18 may form a generallyrectangular footprint for containing the airflow. A tunnel 19 may bedefined within the volume enclosed within an interior defined by the fan12 and the three sections 14, 16, and 18 of the wind tunnel device 10and may enable airflow to pass therethrough. The tunnel 19 may becyclical such that a volume of airflow moves from the fan 12sequentially into the sections 14, 16, 18, and from section 18, theairflow may re-circulate back into the fan 12 without allowing thepassage of particulates or airflow to the exterior of the device.Providing a cyclical circuit enables the airflow to be reused, whichreduces the amount of air exiting the wind tunnel device 10 andminimizes particulate exposure. In some implementations, seals may beprovided between the sections to further minimize the possibility thatparticulates or circulating airflow will be transported outside the windtunnel device 10.

The fan 12 of the wind tunnel device 10 may include a motor 20configured to drive the fan 12, which may be communicatively coupled toa control system or an operating console of the wind tunnel device 10(see FIG. 8). In a particular embodiment, the fan 12 is manufactured byTwin City Fan M/N (TSL SW Model 542), and is of the inline centrifugaltype. As shown in FIGS. 1 and 5, the fan 12 may be joined to the firstsection 14 by a first duct 22 and to the third section 18 by a secondduct 24. In one embodiment, the motor 20 is a 7.5 horsepower motor thatmay be configured to generate wind speeds of between about 1 and 20miles per hour at a spray tip 25 (described below), or between about 1and 14 miles per hour. Those skilled in the art will appreciate that awide variety of commercially available fans with horsepower requirementsranging from 5 horsepower to 30 horsepower, or at about 5, 7.5, 10, 15,20, 25, 30 horsepower may be used in connection with the wind tunneldevice 10. Typically, the wind speed in the other portions of the flowcircuit defined by the wind tunnel device 10 is equal to that of thetest section, which is described further below in connection with thesecond section 12. However, in some implementations, flow may beexpanded through a portion of the flow circuit and may be contractedthrough a duct or other air flow control device upstream from the testsection.

The first section 14 of the wind tunnel device 10 may include a firstcorner 26, a first middle section 27 and second corner 28. As shown inFIGS. 1, 2 and 5, the first corner 26 may be joined to the second corner28 by way of the first middle section 27 and may form one side of thegenerally rectangular shape of the wind tunnel device 10. A portion ofthe tunnel 19 is formed within the volume enclosed by the first section14. As shown in FIGS. 1, 2, 3 and 5, each corner 26, 28 is generallyrectangular, may define a generally rectangular cross-section and maydefine openings at right angles relative to one another. As shown inFIG. 5, two adjacent sides of a corner 26, 28 form a generally rightangled surface at the exterior of the wind tunnel device 10. In order tolimit wind resistance due to such angles, each of the first and secondcorners 26 and 28 may include turning vanes 29 within an interior of thecorners 26, 28. The turning vanes 29 may be configured as verticallyextending members joined to top ends 26 a, 28 a and bottom ends 26 b, 28b of the first and second corners 26 and 28, respectively. In someimplementations, the turning vanes 29 may be configured as louvers oraerodynamic arcuately shaped vanes. In more specific implementations,the turning vanes 29 may be constant-arc vanes (e.g., high efficiencyprofile (HEP) turning vanes manufactured by Aerodyne). Other turningvane geometries may include, but are not limited to, single thicknesscircular arc designs, multiple thickness circular arc designs, singlethickness airfoil designs, and multiple thickness airfoil designs. Insome implementations, the turning vanes 29 may be spaced intermittentlyalong a diagonal line from the interior of the corner to the exterior ofthe corner 26, for example, extending between internal intersectionpoints where the outside exterior walls 26 c, 26 d meet and at whichinternal exterior walls 26 e, 26 f meet. The turning vanes 29 may beconfigured to provide minimum loss and disturbance of air flow as theair turns the corner channels. That is, the turning vanes 29 may beplaced at generally right angled surfaces within the corners 26, 28 toreduce wind resistance and direct airflow away from the right angledsurfaces and some turning vanes 29 may be spaced apart within the corner26, 28 to more evenly direct the airflow. In some implementations,airflow may be turned within the wind tunnel device without any turningvanes.

As shown in FIGS. 1, 3, 5 and 6, the second section 16 of the windtunnel device 10 may be configured as a generally rectangular cabinetand may define the test section 38. The test section 38 may join to thesecond corner 28 of the first section 14 and to a first corner 30 of thethird section 18. A portion of the tunnel 19 is formed within the volumeenclosed by the test section 38.

The test section 38 of the second section 16 may generally defineanother side of the rectangular shape of the wind tunnel device 10. Therectangular test section 38 may be configured to include a first portion39 with a honeycomb air stabilizer unit 40 (not shown), a traversing armhousing 42 with a traversing arm 43 holding the spray tip 25 (FIG. 6), asecond portion 44 with a first expansion cutout 45, a second expansioncutout 46, a laser mount 48 that may hold a laser 49, glass wallsections 50 and a spray particle scrubber 51. The test section 38 mayhave an area that is 6 feet high by 3 feet wide by 12 feet long. In someimplementations, the test section 38 may have various dimensions, andpreferably the test section includes a length of at least 36 inches, anda width and a height that are at least one meter.

The first portion 39 of the test section 38 may be configured toaccommodate movement of the traversing arm 43, described below. Inaddition, the first portion 39 may generally define a rectangular crosssection with a ceiling at the upper end 38 a of the test section 38, afloor at the lower end 38 b of the test section 38, and a pair ofopposing sidewalls arranged therebetween. In some implementations, glasswall sections 50 may be provided as the sidewalls of the first portion39.

The honeycomb stabilizer unit 40 may generally be placed at the entranceto the test section 38. For example, the honeycomb stabilizer unit 40may generally be positioned at the interface where the second corner 28of the first portion 14 joins to the rectangular test section 38. Theunit may include a honeycomb structure that allows air to pass throughthe structure, and may facilitate a more uniform and straight air flowfrom the second corner 28 into the test section 38. In one embodiment,the air stabilizer unit, or flow conditioner, may ensure bothstraightness and uniformity of the airflow as it passes the spray tip.The honeycomb stabilizer unit 40 may have a size and shape similar orthe same as a cross-section of the wind tunnel, and may include ahoneycomb structure with cells of various configurations. For example, aseries of hexagonally-configured cells may each have dimensions of about2 inches by about 0.25 inches. In addition to the hexagonal cellgeometry, the cells may have square and round geometries, and mayinclude cells sizes adapted for flow conditioning that may include athicknesses likely ranging between 1″ up to 4″×¼″, ⅜″, ½″, ¾″ and 1″.Materials that may be used to fabricate the cells may include, but arenot limited to, aluminum, polycarbonate, PVC, ABS, polypropylene,stainless steel, and titanium.

The traversing arm housing 42 may be joined at the first portion 39 at afirst end 38 a of the test section 38, as shown in FIGS. 1 and 3. Thetraversing arm housing 42 may be configured to guide the traversing arm43 into the space defined by the first portion 39 of the test section38. In some implementations, the traversing arm housing 42 may include atrack for guiding the traversing arm 43 and a seal arranged at anopening where the traversing arm 43 enters the test section 38. The sealbetween the housing 42 and the traversing arm 43 ensures sprayparticulates do not escape the test section during spraying and testing.

The traversing arm 43 may extend from the traversing arm housing 42 andmay receive the spray tip 25. In some implementations, the spray tip 25is offset from the traversing arm 43, for example by about 6 to 8inches. In this example, the spray tip 25 may be coupled to thetraversing arm 43 via a conduit such as a rigid conduit projectinghorizontally from the traversing arm 43 and fluidly coupled to the spraytip 25. In further implementations, the traversing arm 43 or the conduitis adapted for the interchangeable attachment of spray tips and mayinclude a supply line coupled to a fluid delivery system for deliveringfluid to the one or more spray tips joined thereto. The spray tip 25 maybe configured to emit a spray forming spray particulates, and the spraytip 25 may be selected from a variety of spray tips (e.g., nozzles) suchas those used in agricultural applications.

The traversing arm 43 may be controllably lowered and raised between thefirst end 38 a of the test section 38, which may be proximate a ceilingof the first portion 39 of the test section 38, and a second end 38 b ofthe test section 38, which may be proximate a floor of the first portion39. This movement may be through the use of a stepper motor (not shown),which moves the traversing arm 43 along the traversing arm housing 42.

In some implementations, the traversing arm 43 may be shaped similar toan airplane wing as shown in FIG. 6. For example, an airfoil shapedtraversing arm 43 produced by Carlson Aircraft. Some suitable airfoilshapes for the arm 43 may be symmetrical circular arc shapes,symmetrical polynomial generated shapes, symmetrical matched ellipseshapes, and symmetrical NACA (National Advisory Committee forAeronautics) airfoil shapes. The airfoil shape of the traversing arm 43may provide less disruption to the air flow within the test section 38.However, other shapes may also be used for the traversing arm 43. Infurther implementations, the traversing arm housing 42 and traversingarm 43 may be fully enclosed within the test section 38. In thisimplementation, the traversing arm 43 may move along the traversing armhousing 42 within the test section 38, which may further minimize thepossibility that particulates from the spray tip 25 will be transportedoutside the wind tunnel device 10.

The second portion 44 of the test section 38 may be configured as afully enclosed testing region of the test section 38 where the sprayparticulates are analyzed. The second portion 44 includes a firstexpansion cutout 45 and a second expansion cutout 46 protrudingoutwardly from the first and second ends 38 a, 38 b of the test section38 proximate a floor and a ceiling of the test section 38, respectively.The second portion 44 of the test section 38 with the expansion cutouts45, 46 accordingly defines a space with cutouts forming an angledceiling and an angled floor separated by sidewalls. The sidewalls of thesecond portion 44 may include the glass wall sections 50 in an areaproximate where the spray analysis is conducted, described below. Theconfiguration of the second portion 44 of the test section 38accommodates the spray angles provided by the spray tip 25 joined to thetraversing arm 43. In contrast, the space defined by the first portion39 of the test section 38 may be unable to accommodate the spray anglesprovided by the spray tips 25 due to height limitations. For example,because the first portion 39 of the test section 38 is configured toallow the traversing arm 43 to translate between the first and secondends 38 a, 38 b of the test section 38, angled spray emitted from thespray tip 25 may otherwise contact the first and second ends 38 a, 38 bof the cabinet 30, e.g., the first portion 39 may define an area that issmaller than an area covered by the angled spray particulates. Theexpansion cutouts 45, 46 downstream from the spray tips 25 areconfigured to minimize such contact by the spray particulates.

The expansion cutouts 45, 46 may be configured as a five wall expansionpiece with an opening for positioning over an opening in an upper orlower end 38 a, 38 b of the test section 38. Walls of the expansioncutouts 45, 46 include angled sides that define an expansion angle 52that is approximately equal to the widest spray angle emitted by thespray tip 25 used in connection with the traversing arm 43. In someimplementations the spray tip 25 may deliver a maximum spray angle of140° and the expansion cutouts 45, 46 may be configured to accommodatethis or other maximum spray angles. In some implementations, theexpansion angle for the cutout may be about 45°. However, the expansionangle may vary from about 10° to about 90°. The depth of the expansioncutouts may be about 12 inches, and the size of the rectangles cut intothe test section wall for receiving the expansion cutout may be about 12wide by about 48 inches long. In some implementations, the cutouts 45,46 may be configured with the same shape. The first expansion cutout 45may include a drip tray that prevents any spray that impinges on thetest section walls from dripping through the measurement area. Thesecond expansion cutout 46 may include a drain for draining thecollected liquid. In some implementations, the first expansion cutout 45may define a small opening that may generally be capped, which may allowfor a suction system to condition the flow past the first expansioncutout 45, for example.

The expansion cutouts 45 and 46 in combination with the second portion44 of the test section 38 may be configured to allow the spray from wideand narrow angle spray tips 25 to be analyzed within the second portion44 of the test section 38 without the spray bouncing off or collectingand dripping from the ceiling and the floor of the test section 38. Forexample, as a wide angle spray tip 25 is spraying a fluid (e.g., aherbicide) when it is at the top end 38 a of the test section 38, thespray pattern of the herbicide may follow one or both of the angledexpansion cutouts 45, 46 and the spray pattern may be allowed to flowalong the expansion cutouts 45, 46 and the second portion 44 so that thespray pattern may be analyzed by the laser 48 and the particulates mayexit the second portion 44. For example, the configuration of theexpansion cutout 45 may prevent some droplets from forming on theceiling of the first end 38 a of the test section 38 above the spacecovered by the laser 49 by allowing the droplets to pass into and out ofthe expansion cutout 45. Similarly, the expansion cutout 46 may beconfigured at an angle at the second end 38 b of the test section 38 toprevent splatter from the herbicide hitting the floor of the second end38 b of the test section 38 and enter the space covered by the laser 49by allowing the droplets to pass into and out of the expansion cutout46. The expansion cutouts 45, 46 may thus be configured to limitmeasurement errors due to errant drops (e.g., droplets that drip downfrom walls or bounce off of walls) passing through the laser path suchas preventing fluid drops from forming as a result of hitting theceiling or floor of the top and bottom ends 38 a, 38 b of the testsection 38 and entering the space covered by the laser 49. Further,while some particulates may contact the drip tray of the first expansioncutout 45, the drip tray may prevent drop formation and channel theparticulates downstream from the testing region thereby preventing suchdrops from falling in the space covered by the laser. Other particulatescontacting the second expansion cutout 46 may be collected and drained.

The laser mount 48 of the test section 38 may be positioned proximatethe second portion 44 of the test section 38 and may be configured toreceive a laser 49 or other analysis devices. The laser mount 48 may bemovable horizontally and/or vertically at least along the glass sections50 of the second portion 44 to enable the laser 49 to measure sprayparticulates from various types of spray tips. For example, some spraytips 25 may deliver a sheet of liquid from an orifice and the sheet maybreak apart into spray particulates at a certain distance away from theorifice of the spray tips 25. In this example, the laser mount 48 andthe laser 49 may be moved horizontally to a position along the secondportion 44 corresponding to a location downstream from the nozzle wherethe spray particulates form. In some implementations, the laser mount 48may translate horizontally from 0 to 24 inches from the spray tip, 2 to18 inches from the spray tip or any combination thereof. In someimplementations, the laser mount 48 may translate vertically while thespray tips remain stationary. While the analysis device described hereinis a laser, it will be appreciated that other analysis devices may beused such as video imaging.

The glass sections 50 of the test section 38 may be configured to enableanalysis, such as laser analysis, of the spray particulates withoutforming openings within the sidewalls of the test section 38. The glassused in the wind tunnel device 10 may be a ⅜″ nominal thickness,low-iron, annealed, soda-lime glass. Acceptable glass configurations forthe test section may include, but are not limited to, ¼″ nominalthickness, ⅜″ nominal thickness, and ¾″ nominal thickness, andsubstantially equivalent metric sized materials. Acceptable compositionsfor the glass may include, but are not limited to, soda-lime, low-ironsoda lime, and borosilicate. In some implementations, fused quartz andsapphire may be used in areas to where the laser analysis takes place.Low iron glass may be preferred due to its increased opticaltransmission. In addition, available tempers are annealed, strengthened,and tempered, but annealed glass is preferable due to its low opticaldistortion for the laser. Some installations may use tempered glass, forexample, as a safety precaution. By analyzing the spray particulateswithin an environment separate from the user and from the analysisdevice, analysis may be performed by the user without risking exposureto potentially harmful chemicals and the analysis device remains free ofspray particulates, which may facilitate avoiding inaccuratemeasurements. While providing glass sections 50 along sidewalls of thesecond portion 44 of the test section 38 is preferred, other areas ofthe test section 38 may also include glass sections. For example, asshown in FIG. 6, the first portion 39 of the test section 38 may includesidewalls formed of glass sections 50 such as optical glass wallsconfigured to enable the user to view movement of the traversing arm 43.In some implementations, the glass sections 50 may be hinged to allowaccess to the interior of the test section 38, for example, to allowattachment of spray tips 25 and maintenance.

A spray particle scrubber 51 of the test section 38 may be joinedbetween the second portion 44 of the test section 38 and the thirdcorner 30 of the third section 18. In some implementations, the sprayparticle scrubber 51 may be configured to collect the droplets exitingthe second portion 44 of the test section 38 and may prevent thedroplets from continuing through the tunnel 19 defined by the windtunnel device 10. With the use of a spray particle scrubber 51, the airmay be reused and provided to the fan 12, for example. In oneembodiment, the scrubber 51 may be configured as a mist extractor. Inanother embodiment, the scrubber 51 may be 99.7% effective at removingparticles greater than 5 μm diameter. For example, the spray particlescrubber 51 may use a series of angled channels to change the flow pathof the particles, allowing them to settle out and run down the channels,into the waste disposal unit.

As shown in FIG. 7, a computer 52 may be configured as an operatingconsole for the wind tunnel device 10 and may be communicatively coupledthereto. The computer 52 may include a processor, a memory and a networkconnection. In some implementations, the computer 52 may be used tooperate the traversing arm 43, the laser mount 48, the laser 49, a fluiddelivery system for delivering fluid to the spray tips 25 and so on. Forexample, using the computer 52, an operator may adjust the position ofthe laser mount 48 and the laser 49 horizontally and vertically. Thismay protect the laser 49 from being handled while readjusting andrepositioning the laser 49. In some implementations, the laser 49 may beoperated using proprietary Sympatec software, WINDOX provided on thecomputer 52. In addition, the computer 52 may be configured to controlthe traversing arm 43 to lower and raise the spray tip 25 joinedthereto. A traversing arm motor (not shown) may also be operated usingsoftware on the computer 52.

As shown in FIGS. 1 and 4, a control box 60 is mounted to the exteriorof the wind tunnel device 10 and may be used to control the wind speedand a waste pump (not shown). The control box 60 may be operated usingthe computer 52 or may be operated separately therefrom.

As shown in FIGS. 1, 4 and 5, the third section 18 of the wind tunneldevice 10 may include a third corner 30 and a fourth corner 32 connectedby a second middle section 34. As shown in FIG. 5, the third corner 30,the fourth corner 32, and the second middle section 36 may defineanother side of the generally rectangular shape of the wind tunneldevice 10. A portion of the tunnel 19 is formed within the volumeenclosed by the third section 18. Similar to the first and secondcorners, each of the third and fourth corners 30 and 32 may includeturning vanes 29. The third section 18 provides a connection between thefan 12 and the second section 16 to enable airflow to be re-circulatedwithin the wind tunnel device 10. In some implementations, an exhaustsystem may be joined to the third section 18 to provide for safe removalof vapors or other contents in the airflow prior to re-circulating theairflow to the fan 12.

The wind tunnel device 10 disclosed herein provides several advantagesover prior approaches. Because the device 10 is configured tore-circulate airflow, ambient air (e.g., air from an externalenvironment in varying climates) need not be pumped into the device 10from external sources, or at least a reduced amount of air is pumpedinto the device. For example, during summer and winter months whenambient temperatures are warm or cold, air within the device 10 may bereused, which avoid cooling and heating airflow prior to itsintroduction into the device 10. A further advantage provided by thedevice 10 is the ability to provide the laser in a separate environmentfrom the interior of the device. This prevents the laser from foulingfrom spray particulates. In addition, because the laser may be mountedto the laser mount 48, the laser may be moved to multiple positions,which is in contrast to prior approaches in which lasers were staticallymounted within a chemical hood. Yet another advantage provided by thedevice 10 is the ability to move the spray tip 25 within the device,including use of wide angle spray tips (110 to 140°) without fouling thetest section. This differs from prior approaches in which the spray tipis mounted in one position, which may be problematic for leveling.Another advantage of the device is that the fully enclosed test chamber,facilitated by the optically clear glass, allows safe testing of activepesticide products.

Implementation of Use

In one implementation of use, the fan 12 may be operated by the motor 20to force air through the tunnel 19 defined by the wind tunnel device 10.A spray tip 25 is attached to the traversing arm 43 of the test section38. A conduit system adapted to transport fluids delivers fluid to thespray tip 25 to be sprayed therethrough. In some implementations, fluidmay be forced to travel through the conduit system using an aircompressor, pumps and so on. For example, the fluid to be delivered tothe spray tip 25 may be tank mixed and pressurized within the tank, theconduit system or both. The conduit system may be coupled to a flowmeter in order to measure the flow rate and pressure of the fluidpassing therethrough prior to exiting the spray tip 25. In general, thespray tip 25 configuration determines the flow rate and the pressure ofthe exiting spray. The use of a flow meter provides confirmation thatthe fluid passing through the conduit system is moving properly, or sothat any pressure drops may be accounted for when analyzing the sprayexiting the spray tip 25. This enables the user to comply with ASAE/ANSIS572.1 test standard for quality control and size classification ofagricultural nozzles, which may vary in quality when purchased from themanufacturer.

Using a computer 52, the traversing arm 43 is vertically lowered andraised within the first portion 39 of the test section 38 so that thatspray tip 25 travels from the first end 38 a of the test section 38 tothe second end 38 b of the test section 38. A fluid, such as anherbicide, is sprayed and the airflow passes the spray tip 25 at between1 and 14 miles per hour. The spray tip 25 delivers spray at about a 110°spray angle, which may exit the spray tip in a vertical orientation.However, the spray angle delivered may exceed 140°, for example,depending on the spray tip and fluid sprayed therefrom.

The airflow carries spray particulates from the spray tip 25 into thesecond portion 44 of the test section 38 with the first and secondexpansion cutouts 45, 46. The expansion cutouts 45, 46 of the secondportion 44 may substantially prevent droplets from forming on theceiling above the space covered by the laser 49, and the expansioncutout 46 prevents droplets from bouncing off the floor and into thespace covered by the laser 49. In some cases, the spray area may belarger than the second portion 44 of the test section 38 with the firstand second expansion cutouts 45, 46, and may impinge upon the testsection floor and ceiling but the particulates may be collected in adrip pan and channeled away from the test section. Prior to measurementof the spray particulates, the computer 52 is used to position the laser49. The computer 52 is used to collect readings and determine particlesize, which may then be analyzed. In some embodiments, the analysis maybe used to classify the spray particle size as “Very Fine,” “Fine,”“Medium,” “Coarse,” and “Very Coarse.”

The spray particulate measurements primarily may be taken whiletraversing the arm vertically up or down. Generally, for full-patternanalysis, the spray pattern measured during the run must clear the lasermeasurement area, prior to and after the run. The laser analysis may betriggered by the spray entering the test area and stopped when the sprayexits the test area.

The spray can also be measured from a static position in a variety oforientations for other types of analysis. The wind tunnel device 100provided herein is particularly useful for identifying sprayparticulates of various sizes, including particulates having a sizelimit of less than 150 μm and less than 105 μm.

The wind tunnel device 10 provided herein, with the laser mount 48proximate the glass sections 50 of the second portion 44, along with theexpansion cutouts 45, 46, may enable the device 10 to deliver airflowpast the spray tip 25 at a speed of between about 1 and 14 miles perhour, which corresponds to low testing speeds. Using low testing speeds,the laser 49 may accurately detect the particle sizes of the sprayparticulates within the testing region.

In addition, the results of the laser 49 analysis may provide accurateresults because the expansion cutouts 45, 46 may prevent errant dropsfrom passing through the path of the laser, described above.

Providing glass sections 50 proximate the laser mount 48 enables thelaser 49 to analyze the spray particulates without the particulatescontacting the laser 49. Users of the wind tunnel device 10 are alsoprotected from exposure to the spray particulates due to the enclosedspace formed by the series of joined segments forming the wind tunneldevice 10.

The cyclical or rectangular shape of the wind tunnel device 10 furtherprovides a system that re-circulates airflow, as described above. There-circulated airflow entering the fan 12 may be clean using the sprayparticle scrubber 51 positioned downstream from the testing region 44and upstream from the fan 12.

The following Example Embodiment provides an implementation in which thewind tunnel device 10 is used to analyze spray particulates from variousspray tips; however, this Example Embodiment should not be construed aslimiting.

Example Embodiment

In a particular embodiment, a wind tunnel device designed as low speedwind tunnel provided wind speeds from 1 to 14 miles per hour at thespray tip and included a laser analyzer, i.e., a Sympatec Helos Vario-KRlaser diffraction particle size analyzer with an R7 lens, mounted on anautomated adjustable base that moved the laser from 0-18 inches from thespray tip. The wind tunnel device was a cyclical closed system with adownstream spray mist extractor removing 99.7% of all spray particlesdown stream of the test section. The area used for spray particlemeasurements was 6 feet high by 3 feet wide with upper and lowerexpansion areas that allow for traversing of up to 140° angle spraytips. The study observed the percentage of droplets within a size limitof less than 150 μm and less than 105 μm. Droplets sized below thesethresholds are generally undesirable in spray applications due to theirpotential to contribute to spray drift.

In this example, two spray tips were analyzed and a drift reducer wasalso analyzed using the spray tips. The tests were conducted with thespray tips traversed at the bottom of an aerodynamic arm joined to thecabinet of the wind tunnel device. The wind speed, spray pressure,traversing arm, and laser operation were controlled by a control paneloperated by a user. The waste water was removed from under the extractorby an enclosed system. The water is pumped from the enclosed containerinto shuttles which are then shipped away for disposal.

The results of spray particulates produced by two different spray tips,spray tip 1 (XR11002) and spray tip 2 (AIXR11004) are provided in Table1 below.

TABLE 1 Examples of Spray Particle Analysis Water Compared to HerbicideFormula Through Two Spray Tips @ 40PSI Volume Medi- % particles < %particles < an Diameter Treatment 105 μm 150 μm (VMD)* Spray tip 1(XR11002) Water 19.9 41.4 168.7 Glyphosate + 22.8 46 158.4 AMS Spray Tip2 (AIXR11004) Water 1.3 3.8 494.4 Glyphosate + 2.7 7.6 387.6 AMS *VMD =Half of spray volume is smaller and half the spray volume is larger thanthis number

Table 1 illustrates the use of the wind tunnel device for testing thetwo different spray tips, which results in the detection of a largedifference for the production of droplets smaller than 150 μm. Spray tip1, XR11002 (XR TeeJet Extended Range Flat Spray Tip), spraying water andGlyphosate+AMS resulted in over 40 percent of the droplets having a sizeof less than 150 μm and about 20 percent of the droplets having a sizeof less than 105 μm. Spray tip 2, AIXR11004 (AIXR TeeJet Spray Tip),spraying water resulted in 3.8 percent of the droplets having a size ofless than 150 μm and about 1.3 percent of the droplets having a size ofless than 105 μm. For the same spray tip, spraying Glyphosate+AMSresulted in 7.6 percent of the droplets having a size less than 150 μmand 2.7 percent of the droplets having a size of less than 105 μm.

The results of herbicide spray particulates produced without and with adrift reducer (AG2013) using two different spray tips, spray tip 1(XR11002) and spray tip 2 (AIXR11004) are provided in Table 2 below.

TABLE 2 Examples of Drift Reduction Adjuvant Reducing % of Fines in aSpray Mixture Volume Medi- % particulates < % particulates < an DiameterTreatment 105 μm 150 μm (VMD)* Spray tip 1 (XR11002) Glyphosate + 22.846 158.4 AMS (control) Glyphosate + 13.2 34 182.1 AMS + AG02013 SprayTip 2 (AIXR11004) Glyphosate + 2.7 7.6 387.6 AMS (control) Glyphosate +0.7 2.8 459.4 AMS + AG02013 *VMD = Half of spray volume is smaller andhalf the spray volume is larger than this number

Table 2 illustrates the use of the wind tunnel device for testing thecontrol herbicide and the herbicide with the drift control agent(AG2013) results in the detection of a large reduction of herbicidedrift using the control agent.

Although the present disclosure provides references to preferredembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scopeof the invention.

1. A wind tunnel device comprising: a testing region comprising: a firstportion carrying a spray tip configured to deliver a spray in thetesting region; and a second portion adapted to receive the spray andaccommodate an area covered by the spray, wherein the wind tunnel deviceis configured such that airflow from an airflow system carries the spraythrough the testing region, and wherein the wind tunnel device isconfigured such that the airflow exiting the testing region isre-circulated using the airflow system.
 2. The device of claim 1,wherein the airflow is carried past the spray tip at between about 1 andabout 20 miles per hour.
 3. The device of claim 1, wherein the airflowsystem comprises a fan.
 4. The device of claim 3, wherein the fan iscontrolled by a computer.
 5. The device of claim 1, wherein the windtunnel device further comprises an analyzer configured to analyze thespray particulates in the testing region.
 6. The device of claim 5,wherein the analyzer comprises a laser.
 7. The device of claim 6,further comprising a computer configured to control the laser.
 8. Thedevice of claim 1, further comprising a computer configured to controlone or more of an arm coupled to the spray tip or a fluid deliverysystem fluidly coupled to the spray tip.
 9. The device of claim 1,wherein at least a portion of the testing region comprises transparentsidewalls.
 10. The device of claim 1, further comprising an armconfigured to interchangeably receive a plurality of spray tips.
 11. Thedevice of claim 1, further comprising a traversing arm configured toreceive the spray tip.
 12. The device of claim 1, wherein the testingregion is adapted to accommodate a plurality of spray patterns.
 13. Thedevice of claim 12, wherein at least a portion of the testing region isenlarged relative to other portions of the wind tunnel device.
 14. Amethod of analyzing spray particulates in a wind tunnel comprising:using a spray tip to deliver a spray in a testing region, the testingregion adapted to receive the spray; analyzing the spray as airflowcarries the spray through the testing region; and using an airflowsystem to re-circulate the airflow through an enclosed interior of thewind tunnel.
 15. The method of claim 14, wherein the step of analyzingis performed by a laser.
 16. The method of claim 14, further comprisingusing a computer to control one or more of an arm carrying the spraytip, a laser mount, a laser, or a fluid delivery system fluidly coupledto the spray tip.
 17. The method of claim 14, wherein the airflow iscarried past the arm at between about 1 and about 20 miles per hour. 18.A wind tunnel, comprising: a traversing arm adapted to receive a spraytip and to traverse into an area defined by a testing region; a firstexpansion attached to the testing region; and a second expansionattached to an opposite side of the testing region from the firstexpansion, wherein the first and second expansions enable sprayparticles from the spray tip to pass through the testing region.
 19. Thewind tunnel of claim 18, further comprising an analyzer.
 20. The windtunnel of claim 18, further comprising a fan.